A possible new threat to Cape vineyards? 15 May 2008

Survey of vines affcted by Aster Yellows under way

There is concern in the wine industry that the occurrence of the dreaded Aster Yellows plant disease in grape vines is being under-stated and that unless the scale of the problem is urgently gauged and  remedial measures instituted, it may have wider production consequences.    

Plant South Africa, which certifies planting material has issued a media release about the situation, saying the national department of agriculture, in collaboration with researchers of Stellenbosch University and VinPro are continuing with further investigations after the disease was first spotted in the vineyards two years ago.

It seems as if there are financial problems getting funding for the research. Nico van Rensburg, manager of Plant SA, says: ‘A survey to determine the magnitude of the problem in vineyards in the Western Cape, as well as a study to find the biological vector of the disease, in collaboration with Winetech, will start in the near future.’

Aster Yellows is a phytoplasma disease and can harm various agricultural crops. This phytoplasma occurs on host plants, including weeds, cover and vegetable crops, as well as flowers. Phytoplasma diseases of the grape vine are found in Europe, and, especially in France, Italy and Spain, where losses are suffered if it not controlled. Often vines have to be removed.

Officials of the Directorate of Plant Health of the Department of Agriculture say phytoplasma is not dangerous to humans, animals, or the environment. ‘In cases where control measures are applied effectively, vineyards can recover completely and the disease will have no effect on the grapes or the quality of wine.’